Internal combustion engine



Sept. 3, 1.935. E. P. LITTLEFIELD 2,013,541

INTERNAL COMBUSTION ENGINE Filea July 5, 19:54

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- Tnventor- Edward R Littlefield,

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Patented Sept. 3, 1935 PATENT OFFICE INTERNAL COMBUSTION ENGINE I Edward P. Littlefield, Saugus, Masa., signor to General Electric Company, a corporation of New York Application July 5, 1934, Serial No. 733,736

BClaiml.

'I'he present invention relates to internal combustion engines comprising a plurality of cylinders, a crank shaft connected to the pistons in the cylinders and a cam shaft driven froni/ the 5 crank shaft for operating various valves connected to the cylinders. More specifically, the invention relates to the -above type of internal combustion engines which includes a timing gear on the cam shaft and an ignition system oper- 10 ated in response to movement of the cam shaft for effecting a succession of timed ignitions in the cylinders.

The object of my invention is to provide an improved construction and arrangement of a i5 timing gear and an ignition system in the type of engines mentioned above which is reliable in operation and can be manufactured at comparatively low cost. 'I'his is accomplished in accordance with my invention by uniting the timing gear and certain elements of the ignition system into a single unit, more specifically by the provision of a timing gear made at least partly of insulating material and using the insulated portion of the timing gear as a support for certain elements of the ignition distributing system.

For a better understanding of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 represents a perspective view, partly diagrammatic, of a part of an internal combustion engine embodying my invention; Fig. 2 is a front view; and Fig. 3 is a sectional view of Fig. 2.

The arrangement comprises a timing gear III secured to an overhung end portion of a cam shaft II by means of a key I2 and-a screw I3. The timing gear I is driven in well known manner from the crank shaft by any suitable means, in the present instance by means including a drive gear I4, meshing with the timing gear I0. The cam shaft I I projects through an opening in a casing wall I of the engine and is supported on said wall through the intermediary of a bearing bushing I6.

The timing gear III, according to my invention, comprises a steel hub I1 which is molded into a body made of insulating material such as a material including a phenolic condensation product or an artificial resin. 'I'he insulating body comprises a web IB and an outer rim I 9 with teeth 20.

As stated above, the timing gear is united with and forms an element of an ignition distributing system. This ignition distributing system in the present instance comprises a metal or electric contact ring 2| integrally united with a radially spaced short segment 22 by a bridge 23. The ring 2| with the segment 22 and the bridge 23 is supported on, more specifically, and molded into,

the front face of the web I8.

'I'he front face of jections or cam members 24. In the present instance I have indicated six projections which are uniformly angularly spaced, and concentrically arranged with both the cam shaft and the metal ring 2|. The metal ring 2|, the segment 22 and the aforementioned cam members or projections 24 form parts of the ignition distributing system. The latter has a primary circuit and a secondary circuit. The primary circuit, as diagrammatically indicated in Fig. l, includes a. source of electric energy, such as a battery 25, which on one si-de is grounded by a wire 26 and on the other side is connected to one end of a primary coil 21 of an ignition transformer 2B. The other end of the coil 21 is connected to a circuit interrupting contact or breaker point 29 cooperating with a breaker point 30, which latter is grounded by a wire 3l. A grounded capacitor 32 is connected to a point intermediate the primary coil 21 and the breaker point 29. The breaker point 29 is secured to a projection 33 of a plate 34 made of insulating material similar to the material of the body of the timing gear. The insulating plate 34 is disposed in front of the gear face. The breaker point 30 is secured to or forms a part of an arm 35 which is suitably supported on a fulcrum 36 held on the plate 34. Another portion of the arm 35 is disposed adjacent the face of the hub I1 and is biased toward said face by a spring 31. In the position indicated, the breaker points or circuit interrupting or making and breaking contacts 29 and 3l) engage each other, permitting a flow of current from the battery 25 through the primary coil 21, through the breaker points and the ground. During rotation of the shaft II the arm 35 is successively eng-aged by the projections 24, causing the arm to swing automatically back and forth to effect opening and closing of the primary circuit.

As stated before, both breaker points are mounted on the plate 34 made of electric insulating or nonconducting material. This plate 34 forms a part of a cover enclosing the timing gear. The other part of the cover is formed by a member or side wall 38 which has a flanged portion 39 secured to the engine casing wall I 5 by screws 40, and another recessed portion 4I to which the plate 34 is fastened by means including a ring 42 and a plurality of screws 44. The breaker points 29 and 30 are disposed in front of the plate 34 and enclosed by a cap 45 screwed onto an annular threaded projection 46 of the plate 34. The electrical connection between the primary coil 21 and the breaker point 29, as shown in Fig. 3, is accomplished by means including a wire 41 connected to a screw 48, which latter contacts a lug 49 having a portion secured to the breaker point 29.

lportion 4| of the member 38.

The secondary circuit of the ignition distributing system comprises a secondary coil 50 of the ignition transformer 28 which has one end connected to ground by a wire 5i and another end electrically connected to the aforementioned metal ring 2i by means including a wire 52 and a brush 53. The brush 53, as shown in Fig. 3, is disposed in a bore of a plug 54 and biased towards the metal ring 2| by a spring 55. The spring is compressed by a nut 56 which is screwed onto an outer portion of the plug and also serves to fasten the end of the wire 52 to the plug. The secondary circuit also includes the aforementioned segment 22 electrically connected with the ring 2| by the bridge '23 and six brushes 51 supported on the plate 34 and bearing against an annular portion of the web i8, which annular portion includes the segment 22. Thus, during rotation of the web the segment 22 engages successively the different uniformly, angularly spaced brushes 51. The segment 22 and the ring 2i form a part of the secondary circuit interrupting means Each of the six brushes 51 is connected to a spark plug 58 by a wire 59. One electrode of each spark plug is grounded, as indicated at 60. When the segment 22 contacts one of the brushes 51, the secondary circuit is closed and current flows from one end of the coil 50 through the brush 53, the ring 2|, the bridge'23, the segment 22, one of the brushes 51, the corresponding wire 58 and the corresponding spark plug 58 through the ground to the other end of the secondary coil 50.

The plate 34 has a sliding t in the recessed Adjustment of the ignition by advancing and retarding of the spark may be accomplished by rotating the plate 34. To this end a spark-retarding and advancing lever 6| (Fig. 2) is secured to the plate 34 by means of pins 62. The lever 6I may be moved by hand or by well known automatic means, not shown, to change the relative position between the secondary brushes 51 and the segment 22 which latter being fixed to the timing gear has a definite relation to the position of the cylinder pistons, not shown.

Timing of the engine is effected in the usual manner by changing the relative position between the cam shaft and the crank shaft, for example, in the present instance, by demounting the gear I4 to effect disengagement between this gear and the timing gear and thereafter slightly turning the crank shaft, and again mounting the gear I4 tomesh with the timing gear i0'.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an internal combustion engine, the commination of a cam shaft, a timing gear with a web being secured to the shaft, and an ignition distributing system including means secured to the web of the timing gear. i

2. In an internal combustion engine, the combination of a cam shaft, a timing gear secured to the shaft, the timing gear having a web made of insulating material, and a hub having a face with a plurality of angularly spaced 4projections, and an ignition distributing system comprising a primary circuit with breaker points and a fulcrumed arm supporting one of the breaker points and being actuated by said projections.

3. In an internal combustion engine, the combination of a cam shaft, a timing gear secured to the shaft, the timing gear having a web made of insulating material, and an ignition system comprising a secondary circuit including a metal ring and a segment concentrioally spaced from the ring and electrically connected therewith, the segment and the ring being supported on said web.

4. In an internal combustion engine, the combination of a casing, a cam shaft supported on and projecting through the casing, a timing gear secured to an overhung portion of the shaft, means enclosing the gear comprising a member fastened to the casing and a plate made of insulating material and disposed in front of the gear, and an ignition distributing system comprising a primary electric circuit including breaker points, one point being fastened to the plate, an arm fulcrumed on the plate and supporting the other point and means on the timing gear for actuating the arm to effect opening and closing of the points during operation.

5. In an internal combustion engine, the combination of a casing, a cam shaft having an overhung portion projecting through the casing, a timing gear having a metal hub secured to the overhung shaft portion and a web made of a material including an artificial resin and united with the hub, means enclosing the gear including a plate disposed in front of the gear and made of a material including an artificial resin, and an ignition distributing system including a ring with a radially spaced segment molded into the web, a n

brush supported on the plate and engaging the ring and a plurality of brushes held on the plate and engaging an annular portion of the web including said segment whereby rotation of the gear causes in succession electric connections between the rst named brush and the other brushes.

6. In an internal combustion engine, a casing, a cam shaft supported on the casing and having a portion projecting out of the casing, a timing gear fastened to said shaft portion and comprising a web made of a material including an artificial resin and a hub with a plurality of angularly spaced projections, an adjustable plate in front of the gear face secured to the casing and made of a material including an artificial resin, and an f ignition distributing system comprising a primary and a secondary circuit, the primary circuit including breaker points supported on the plate and means including said hub projections for opening and closing the breaker points, the secondary circuit including brushes held on said plate and means secured to the web for effecting a succession of connections between one of the brushes and the other brushes.

7. In an internal combustion engine, the combination of a cam shaft, a timing gear having a web made of insulating material and a hub se- EDWARD P. LITTLEFIELD. 

